1. Field of the Invention
This invention pertains to the field of magnetic recording using disk drives and, more specifically, to a method and apparatus for energizing the head actuator of a disk drive so as to optimize movement of the actuator away from a magnetic latch.
2. Description of the Prior Art
It is usual practice in the field of magnetic recording using disk drives that when the disk drive is turned off, the disk drive's actuator arm is moved to a non-data area of the disks, and that the arm is parked at this extreme edge of the disks. The art also contains a number of teachings relative to various latch devices that operate to physically hold the actuator arm in this parked position. The following patents, incorporated herein by reference, are exemplary.
U.S. Pat. No. 4,881,139 describes a latch mechanism for a disc drive wherein a ferrous latch arm's position is controlled between two positions by momentary energization of a coil. The respective position of this latch arm operates to latch or to release a head actuator arm. The coil is momentarily energized in one direction to move the latch arm in one direction so as to set the latch, and the coil is momentarily energized in the opposite direction to move the latch arm in the opposite direction so as to release the latch. In both positions of the latch arm, stray magnetic flux from a head arm actuator motor passes through the latch arm.
The present invention provides variable and controlled energization of the actuator motor that operates to move a head actuator arm away from a magnetic latch. The art teaches variable and controlled energization of such a actuator motor for the purpose of compensating for the trackwise disparity that may exist between inductive recording heads and magneto-resistive playback heads. U.S. Pat. No. 4,802,033 is exemplary.
U.S. Pat. No. 5,003,415 is also noted wherein the current delivered to a voice coil of an actuator motor is adjusted so as to balance the environmental forces acting upon the voice coil.
While the above-described devices are generally useful for their intended purposes, the need remains in the art for a method and an apparatus that optimizes movement of a disk drive's head actuator arm away from a parked position whereat the arm is magnetically latched.